Spot welding apparatus



Feb. 22, 1949. M. BEYMER 2,462,458

SPOT WELDING APPARATUS Filed July 14, 1948 2 Sheets- Shee r. 2

Acource [721/677 for I %0rs/Pa (50 mar Patented Feb. 2 2, 1949 SPOT WELDING APPARATUS Marshall Bcymer, Chicago, Ill., assignor of onehalf to Henry L. Sweitz, Chicago, Ill.

Application July 14, 1948, Serial No. 38,620

4 Claims.

This invention relates to spot welding apparatus, and particularly to such apparatus that is small and portable in character.

In spot Welding apparatus as heretofore utilized, it has been customary to afford opposed electrodes arranged in a substantially vertical relationship so that the work might be placed in position between such electrodes. It has been customary to assemble the parts to be welded on top of the lower invisible electrode in a fixed or stationary position using both of the workers hands and to move the upper electrode down into position in abutment with the upper surface of the work by sOme other means, after which the necessary welding current has been applied to the Work through the opposed and clamping electrodes. While the need for a practical portable spot welding apparatus has long existed, such portable apparatus offered has not been sumciently practical to be acceptable in the trade, and it is, therefore, an important object of the present invention to afford a portable spot welding apparatus that is not only completely simple in character, but which is mechanically capable of convenient and efiective use using but one hand. More particularly, it is an object of the present invention to enable portable spot welding apparatus to be readily, visibly and easily applied to the point of work, using but one of the operators hands, and an object related to the foregoing is to enable a substantial portion of the weight of a portable spot welding apparatus to be supported by the Work and to visibly facilitate the location and clamping of the electrodes on the work as well as the application of the Welding current to the work, thereby freeing the operators other hand for use in holding or otherwise manipulating the parts to be welded.

Another and more specific object of the present invention is to afford a spot welding device that is readily portable in character and which may be supported by one hand in such a way that the electrodes may be visibly placed on and clamped to the work at the point to be welded and the control switch operated by this same hand in a convenient and practical manner, freeing the second hand for purposes concerning the work. Related objects are to utilize the top electrode as a supporting arm for such a portable spot welding apparatus in such a way that the weight of the spot welding apparatus may be readily supported and the electrode clamping and switch operating means readily operated while the worker is supporting a lesser portion of the weight of the apparatus. More specifically, it is an object of the present invention to enable the upper electrode of a spot welding apparatus to be arranged in a fixed relation with respect to the body of the spot Welding apparatus, thereby to enable this electrode to act in part as a means to support in part the weight of the welding apparatus, and the related object is to enable the lower electrode to be conveniently moved by the selfsame supporting hand to its clamping and fusing relation while the upper electrode is in position on top of the work.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show a preferred embodiment and the principles thereof and what I now consider to be the best mode in which I have contemplated applying those principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.

In the drawings:

Fig. 1 is a side elevational view of a spot welder embodying the features of the invention;

Fig. 2 is a view of the left hand or forward end of the welder;

Fig. 3 is a view of the right hand or rear end of the welder;

Fig. 4 is a view taken partially in longitudinal vertical cross section and showing features of internal construction; and

Fig. 5 is a schematic wiring diagram illustrating the electrical features of the apparatus.

For purposes of disclosure, the invention is herein illustrated as embodied in a portable spot welder Ill having a main body II with a lower stationary handle 12 extended along the upper side thereof. The body H has a switch enclosing housing 3 at its rear or right hand end as viewed in Fig. 1, while at the forward end, an upper electrode l5U is supported on a stationary horizontal arm ltU in opposed relation to a lower electrode l5L that is supported on a relatively movable arm ISL. The lower arm lGL is carried on a rocking frame 18 that is pivoted at l9 0n the forward end portion of the body ll near the lower edge thereof as will hereinafter be described in detail, and this operating rocker l8 has a handle portion 18H that extends rearwardly over the handle l2 so that it may be moved downwardly to the dotted line position shown in Fig. 1 to effect upward clamping movement of the lower electrode ISL.

The body II is made up in a large measure by a step-down transformer T in which the laminations are arranged in transverse vertical planes so as to be clamped between a front plate 2I and a rear plate 22 by means of longitudinal tie rods 23. The rear plate 22 is formed as a flange on the switch enclosing housing I3, and thus tie rods 23 serve to hold the switch housing It in position. Within the housing I3, a stationary switch contact 2:2 is mounted on an insulating plate 25 which is in turn supported by a bracket 26. On the insulating plate 25 a movable switch element 21 in the form of a spring is arranged for engagement with the contact 24. This spring contact 2'! normally assumes the open position shown in Fig. 4, and an insulating pin 39 that is slidably positioned in the housing I3 extends upwardly near the right hand end of the handle I2 so as to be disposed beneath the rear end of a switch operating lever 3|. This switch operating lever 3| is pivoted at 32 on the lower face of the handle l2, and a projecting forward end 3IH is so disposed that it may be engaged and moved upwardly by the finger of the user so as to thereby force the pin 39 downwardly and effect closure of the switch 2'l2l. The contact 24 is connected as shown in Fig. to one lin wire L-I of an alternating current source, while the other contact Z'Zis connected by a wire 3 4 to one terminal of the primary winding T--! of the transformer T. The other terminal of the primary winding is connected by wire 35 to the other line wire L-Z of'the alternating current source. The secondary T2 of the transformer T is afforded by a single loop of a relatively heavy conductor that may be in the form of a flat woven wire, strand or ribbon, and the ends of this strand or ribbon are extended through the plate 2! and are connected to the two electrodes EU and t 5L as will hereinafter be described.

The forward plate 2! of the body II is formed with a relatively large opening 49 therethrough so that the wires or strands that form the secondary Ta-Z of the transformer may be extended forwardly through this opening for appropriate connection with the upper and lower electrodes. The front plate 2| also is provided with a forwardly projecting and rigidly related mounting arm 42, as will be evident in Fig. 4 of the drawings, and this rigid arm 32 serves as a mounting for the pper supporting arm lSU. Thus the arm I 6U has the rear portion thereof located beneath the arm G2 with a sheet of insulating material 62A therebetween, and a cap screw 43 serves to secure these arms IGU and 42 rigidly together. The cap screw it also serves to secure a conductor plate t4 against the lower face of the arm IBU, and this conductor plate as extends rearwardly and is connected by means of a screw and nut device 45 to one end of the strand that forms the secondary T2 of the transformer. Thus the arm ISU is supported rigidly and in a forwardly projecting relation with respect to the body I I of the apparatus, and the arm ISL is movably supported on the rocker It in a manner that is quite similar to the mounting of the upper arm I 6U. Thus the rocker I8, as shown in Figs. 1, 2 and 4, includes a bottom wall ISB, and the arm IBL extends rearwardly into position over the upper surface of the wall I813, and a sheet of insulating material 42B is disposed therebetween. Cap screws 46 serve to secure the arm ISL in place on the wall I83, and these cap screws also serve to secure a conducting plate 41 to the upper face of the arm ISL. A screw and nut device 48 secures the other end of the transformer secondary T2 to the rear end of the plate 41.

As will be evident in Figs. 1, 2 and 4, the rocker I8 has spaced side walls I8S that extend upwardly from the bottom wall I8B, and these side walls curve inwardly at their forward edges so as to make the forward edge portion of the rocker I8 relatively narrow. These side walls l8S are disposed just outwardly of rigid lugs 25L that are formed on the forward side of the plate 2| near the lower corners thereof, and pivot pins I9 extend through the respective side walls I88 and into the adjacent lugs 2IL to afford the pivotal support for the rocker I8. At the upper edges of the side walls I88, the handl portion I 8H is connected to such side walls by cap screws 39, but it will be apparent, of course, that this handle might be made integral with the side walls IBS in many instances. The handle IBH is of such a shape as to conform with the upper outline of the walls its at the points of connection therewith, and it should be observed that the handle EBH is relatively hollow, as will be evident in Figs. 1 and 3. The handle IfiI-I thus tapers rearwardly to a smaller cross sectional form and is relatively narrow in those portions where the handle l8I-I overlies the handle I2.

The side walls l as are cut away at their forward edges as at I8C in Figs. 1, 2 and 3 to afford a relatively deep, forwardly opening throat rearwardly of the electrodes, thereby enabling spot welds to be formed a substantial distance from the edge of a work piece. Moreover, at their forward ends, and centrally thereof, the side walls ISS are cut away as at ISA and ISX, Fig. 2, thereby to afford clearance for the projecting arms IEU and ISL, respectively. The upper rear edges of the side walls I8S are relieved as at I8Y, Fig. 1, so as to afford clearance and allow the rocker I8 to move through the desired electrode clamping movement.

The handle i2 is afforded by a relatively long horizontal portion that forms the grasping portion, and at its forward end the handle extends down at I2 and is secured to the upper edge portion of the plate 25 by cap screws 52, while at the rear end the handle I2 has a downwardly extending portion I2R that is secured by cap screws 53 to the upper wall of the housing I3.

With the structure that is thus afforded, the apparatus may be conveniently utilized to weld sheets such as WI and W-2, Fig. 1, together. In such use the tool is put into position with the rigid or stationary upper electrode i5U resting on the upper surface of the work, and through this arrangement a substantial portion of the weight of the tool is supported. The worker, of course, supports the balance of the weight of the tool by means of the handle l2, and after the upper electrode ISU has been accurately located, the lower electrode ISL may readily be raised into the desired clamping relationship merely by gripping the handle IilH so as to press the same downwardly, toward the handle l2. After this is done the operator may engage the handle 3IH with one finger so as to close the switch 24 .2l, and the welding current is thus applied to the work through the electrodes l5U and I5L. With the apparatus that is thus provided by the present invention, the workmen may readily locate the spot welds accurately in the desired position, and this may be accomplished in a simple manner and without excessive effort.

Thus, while I have illustrated and described the preferred embodiment of my invention, it is to be understood that this is capable of variation and modification and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

1. In a portable spot welding apparatus, an elongated body including a transformer, a lifting handle extending along the top of said body for lifting the same, an upper electrode extended in a fixed relation from one end of said body, a lower electrode movably mounted on said body below and in operative alignment with said upper electrode, energizing connections from said transformer to said electrodes, and an electrode clamping handle movably mounted on said body and disposed above said lifting handle, said loW- er electrode being mounted on said clamping handle for movement thereby.

2. In a portable spot welding apparatus, an elongated body including a transformer, a lifting handle extending longitudinally along the top of said body for lifting the same, an upper electrode extended in a fixed relation from an upper end portion of one end of said body, a lower electrode disposed below and in operative alignment with said upper electrode, energizing connections from said transformer to said electrodes, and an electrode clamping handle mounted on said body and disposed above said lifting handle, and a rocker pivoted on said body at said one end of said body and on which said lower electrode is fixed, said rocker being operatively connected to said clamping handle for clamping said lower electrode upon predetermined relative movement of said handles.

3. In a portable spot welding apparatus, an elongated body including a transformer and clamping plates at opposite ends of the transformer, a switch housing on the clamping plate at one end of the transformer, a rigid electrode support extended from the upper portion of the plate at the other end, a lifting handle extending along the top of said body for lifting the same, and fixed respectively to said switch box and said electrode support, an upper electrode fixed to said electrode support, a rocker pivoted on a transverse horizontal axis near the lower portion of said plate at said other end, a lower electrode fixed on said rocker below and in operative align ment with said upper electrode, energizing connections from said transformer to said electrodes, and an electrode-clamping handle fixed to said rocker and disposed above said lifting handle for clamping said lower electrode upon predetermined relative movement of said handies.

4. In a portable spot Welding apparatus, an elongated body including a transformer, and clamping plates at opposite ends of the transformer, pivot lugs formed on the clamping plate at one end of the transformer near the lower edge thereof and a rigid electrode sup-port extended from the upper portion of said last mentioned plate, a lifting handle extending along and connected to the top of said body for lifting the same, an upper electrode fixed to said electrode support, a rocker pivoted on a transverse horizontal axis on said lugs near the lower portion of said body at said one end, a lower electrode fixed on said rocker below and in operative alignment with said upper electrode, energizing connections from said transformer to said electrodes, and an electrode clamping handle fixed to said rocker and disposed above and in closely spaced and generally parallel relation with respect to said lifting handle for clamping said lower electrode upon predetermined relative movement of said handles.

MARSHALL BEYMER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,779,365 Von I-Ienke Oct. 21, 1930 2,115,084 Podany Apr. 26, 1938 2,267,297 Campbell Dec. 23, 1941 2,441,438 Mulder May 11, 1948 

